Detectors comprising a photosensitive array having at least one photosensitive surface, whereby a means for focusing a spectrally split light onto the photosensitive array is arranged in a beam path upstream from the photosensitive array, are known in actual practice and are employed, for example, in a confocal microscope for purposes of spectral detection. In this process, downstream from the detection pinhole of the confocal microscope, the light is collimated through a lens, the collimated light is then spectrally split in a dispersing element such as, for instance, in a grating, prism or hologram, and the spectrally split light is focused by means of a lens onto the photosensitive array, for example, a CCD array.
The prior-art systems, however, entail the problem that the achievable spot diameters typically lie in the order of magnitude from 100 μm to 600 μm—depending on the size of the confocal pinhole—in the direction of the spectral splitting as well as in the direction perpendicular thereto. This is many times larger than the size of individual pixels in common photosensitive arrays. Fundamentally, this drawback can be dealt with either by using larger pixels or else by using more pixels in order to read out a single spot. Both approaches, however, significantly increase the requisite readout time per spot, that is to say, per detection wavelength, so that the detection speed is too low for most envisaged tasks.